#define _USE_MATH_DEFINES #include using namespace std; #define FOR(i,m,n) for(int i=(m);i<(n);++i) #define REP(i,n) FOR(i,0,n) #define ALL(v) (v).begin(),(v).end() using ll = long long; constexpr int INF = 0x3f3f3f3f; constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL; constexpr double EPS = 1e-8; constexpr int MOD = 998244353; constexpr int DY[]{1, 0, -1, 0}, DX[]{0, -1, 0, 1}; constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1}, DX8[]{0, -1, -1, -1, 0, 1, 1, 1}; template inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; } template inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; } struct IOSetup { IOSetup() { std::cin.tie(nullptr); std::ios_base::sync_with_stdio(false); std::cout << fixed << setprecision(20); } } iosetup; template struct MInt { unsigned int val; MInt(): val(0) {} MInt(long long x) : val(x >= 0 ? x % M : x % M + M) {} static constexpr int get_mod() { return M; } static void set_mod(int divisor) { assert(divisor == M); } static void init(int x = 10000000) { inv(x, true); fact(x); fact_inv(x); } static MInt inv(int x, bool init = false) { // assert(0 <= x && x < M && std::__gcd(x, M) == 1); static std::vector inverse{0, 1}; int prev = inverse.size(); if (init && x >= prev) { // "x!" and "M" must be disjoint. inverse.resize(x + 1); for (int i = prev; i <= x; ++i) inverse[i] = -inverse[M % i] * (M / i); } if (x < inverse.size()) return inverse[x]; unsigned int a = x, b = M; int u = 1, v = 0; while (b) { unsigned int q = a / b; std::swap(a -= q * b, b); std::swap(u -= q * v, v); } return u; } static MInt fact(int x) { static std::vector f{1}; int prev = f.size(); if (x >= prev) { f.resize(x + 1); for (int i = prev; i <= x; ++i) f[i] = f[i - 1] * i; } return f[x]; } static MInt fact_inv(int x) { static std::vector finv{1}; int prev = finv.size(); if (x >= prev) { finv.resize(x + 1); finv[x] = inv(fact(x).val); for (int i = x; i > prev; --i) finv[i - 1] = finv[i] * i; } return finv[x]; } static MInt nCk(int n, int k) { if (n < 0 || n < k || k < 0) return 0; if (n - k > k) k = n - k; return fact(n) * fact_inv(k) * fact_inv(n - k); } static MInt nPk(int n, int k) { return n < 0 || n < k || k < 0 ? 0 : fact(n) * fact_inv(n - k); } static MInt nHk(int n, int k) { return n < 0 || k < 0 ? 0 : (k == 0 ? 1 : nCk(n + k - 1, k)); } static MInt large_nCk(long long n, int k) { if (n < 0 || n < k || k < 0) return 0; inv(k, true); MInt res = 1; for (int i = 1; i <= k; ++i) res *= inv(i) * n--; return res; } MInt pow(long long exponent) const { MInt tmp = *this, res = 1; while (exponent > 0) { if (exponent & 1) res *= tmp; tmp *= tmp; exponent >>= 1; } return res; } MInt &operator+=(const MInt &x) { if((val += x.val) >= M) val -= M; return *this; } MInt &operator-=(const MInt &x) { if((val += M - x.val) >= M) val -= M; return *this; } MInt &operator*=(const MInt &x) { val = static_cast(val) * x.val % M; return *this; } MInt &operator/=(const MInt &x) { return *this *= inv(x.val); } bool operator==(const MInt &x) const { return val == x.val; } bool operator!=(const MInt &x) const { return val != x.val; } bool operator<(const MInt &x) const { return val < x.val; } bool operator<=(const MInt &x) const { return val <= x.val; } bool operator>(const MInt &x) const { return val > x.val; } bool operator>=(const MInt &x) const { return val >= x.val; } MInt &operator++() { if (++val == M) val = 0; return *this; } MInt operator++(int) { MInt res = *this; ++*this; return res; } MInt &operator--() { val = (val == 0 ? M : val) - 1; return *this; } MInt operator--(int) { MInt res = *this; --*this; return res; } MInt operator+() const { return *this; } MInt operator-() const { return MInt(val ? M - val : 0); } MInt operator+(const MInt &x) const { return MInt(*this) += x; } MInt operator-(const MInt &x) const { return MInt(*this) -= x; } MInt operator*(const MInt &x) const { return MInt(*this) *= x; } MInt operator/(const MInt &x) const { return MInt(*this) /= x; } friend std::ostream &operator<<(std::ostream &os, const MInt &x) { return os << x.val; } friend std::istream &operator>>(std::istream &is, MInt &x) { long long val; is >> val; x = MInt(val); return is; } }; namespace std { template MInt abs(const MInt &x) { return x; } } using ModInt = MInt; template struct Rational { T num, den; Rational(): num(0), den(1) {} Rational(T num, T den = 1) : num(num), den(den) { assert(den != 0); reduce(); } template Real to_real() const { return static_cast(num) / den; } Rational &operator+=(const Rational &x) { T g = std::__gcd(den, x.den); num = num * (x.den / g) + x.num * (den / g); den *= x.den / g; reduce(); return *this; } Rational &operator-=(const Rational &x) { return *this += -x; } Rational &operator*=(const Rational &x) { T g1 = std::__gcd(num, x.den), g2 = std::__gcd(den, x.num); num = (num / g1) * (x.num / g2); den = (den / g2) * (x.den / g1); reduce(); return *this; } Rational &operator/=(const Rational &x) { return *this *= Rational(x.den, x.num); } bool operator==(const Rational &x) const { return num == x.num && den == x.den; } bool operator!=(const Rational &x) const { return !(*this == x); } bool operator<(const Rational &x) const { return (x - *this).num > 0; } bool operator<=(const Rational &x) const { return !(x < *this); } bool operator>(const Rational &x) const { return x < *this; } bool operator>=(const Rational &x) const { return !(*this < x); } Rational &operator++() { if ((num += den) == 0) den = 1; return *this; } Rational operator++(int) { Rational res = *this; ++*this; return res; } Rational &operator--() { if ((num -= den) == 0) den = 1; return *this; } Rational operator--(int) { Rational res = *this; --*this; return res; } Rational operator+() const { return *this; } Rational operator-() const { return Rational(-num, den); } Rational operator+(const Rational &x) const { return Rational(*this) += x; } Rational operator-(const Rational &x) const { return Rational(*this) -= x; } Rational operator*(const Rational &x) const { return Rational(*this) *= x; } Rational operator/(const Rational &x) const { return Rational(*this) /= x; } friend std::ostream &operator<<(std::ostream &os, const Rational &x) { if (x.den == 1) return os << x.num; return os << x.num << '/' << x.den; } private: void reduce() { T g = std::__gcd(num, den); num /= g; den /= g; if (den < 0) { num = -num; den = -den; } } }; namespace std { template Rational abs(const Rational &x) {Rational res = x; if (res.num < 0) res.num = -res.num; return res; } template Rational max(const Rational &a, const Rational &b) { return a < b ? b : a; } template Rational min(const Rational &a, const Rational &b) { return a < b ? a : b; } template struct numeric_limits> { static constexpr Rational max() { return std::numeric_limits::max(); } static constexpr Rational lowest() { return std::numeric_limits::lowest(); } }; } // std ll p3(int n) { ll res = 1; while (n--) res *= 3; return res; } int main() { using rational = Rational<>; map, rational> dp; auto f = [&](auto&& f, const multiset& a) -> rational { if (dp.count(a) == 1) return dp[a]; rational& r = dp[a]; if (a.size() == 1) return r = rational(2, 3); multiset b = a; for (const int ai : a) { b.erase(b.lower_bound(ai)); chmax(r, (-f(f, b) + 2) / 3); FOR(na, 1, ai) { b.emplace(na); chmax(r, (-f(f, b) + 2) / 3); b.erase(b.lower_bound(na)); } b.emplace(ai); } int x = 0; for (int ai : a) x ^= ai; if (x == 0) { assert(r.den == p3(accumulate(ALL(a), 0))); } else { pair rem{0, 0}; for (int ai : a) { if ((x ^ ai) <= ai) { chmax(rem, make_pair(ai - (x ^ ai), ai)); } } for (int ai : a) { if (ai == rem.second) { b.erase(b.lower_bound(ai)); if (rem.first < ai) b.emplace(ai - rem.first); assert(f(f, b).den * 3 == r.den); break; } } } return r; }; auto nth = [](const ll n) -> ModInt { return (ModInt::inv(ModInt(3).pow(n).val) * (n % 2 == 0 ? -1 : 1) + 1) / 2; }; int n; cin >> n; if (n == 1) { cout << ModInt(2) / 3 << '\n'; return 0; } vector a(n); REP(i, n) cin >> a[i]; int x = 0; REP(i, n) x ^= a[i]; if (x == 0) { cout << nth(accumulate(ALL(a), 0LL)) << '\n'; } else { int remove = 0; REP(i, n) { if ((x ^ a[i]) <= a[i]) chmax(remove, a[i] - (x ^ a[i])); } cout << nth(accumulate(ALL(a), 0LL) - remove + 1) << '\n'; } return 0; }